Self-centering steady rest chucks

ABSTRACT

A steady rest for use with a lathe has a non-rotatable housing which is suitably secured to the lathe and which supports for rotation therein a self-centering chuck for securing a work-piece extending through the steady rest. The collet member of the chuck has axially extending fingers which are radially flexed or released respectively to engage or disengage the workpiece on relative axial movement of such collet member and a sleeve surrounding that member, by virtue of the provision of cooperating frusto-conical surfaces on said collet member and said sleeve. An internally threaded adjusting collar engages a corresponding thread on the collet member and abuts the end of the sleeve, so that the collet member is moved axially and the collet fingers move radially when the adjusting collar is rotated relative to the collet member. A pin is radially retractably mounted through the housing for releasable engagement with the sleeve to hold such sleeve stationary and to facilitate tightening or releasing of the collet fingers on the workpiece. A ratchet and pawl mechanism is provided between the adjusting collar and the collet member to prevent their relative rotation and loosening of the collet fingers from the workpiece during operation of the lathe.

United States Patent Kladich [54] SELF-CENTERING STEADY REST CHUCKS [72]Inventor: Joseph Kladlch, 100 Rowena Drive, Don

Mills, Ontario, Canada [22] Filed: June 14, 1968 [21] Appl.No.: 737,071

[52] US. Cl. ..82/38, 279/52 FOREIGN PATENTS OR APPLICATIONS 513,39310/1939 GreatBritain..... ...82/38 [451 May 23, 1972 [57] ABSTRACT Asteady rest for use with a lathe has a non-rotatable housing which issuitably secured to the lathe and which supports for rotation therein aself-centering chuck for securing a workpiece extending through thesteady rest. The collet member of the chuck has axially extendingfingers which are radially flexed or released respectively to engage ordisengage the workpiece on relative axial movement of such collet memberand a sleeve surrounding that member, by virtue of the provision ofco-operating frusto-conical surfaces on said collet member and saidsleeve. An internally threaded adjusting collar engages a correspondingthread on the collet member and abuts the end of the sleeve, so that thecollet member is moved axially and the collet fingers move radially whenthe adjusting collar is rotated relative to the collet member. A pin isradially retractably mounted through the housing for releasableengagement with the sleeve to hold such sleeve stationary and tofacilitate tightening or releasing of the collet fingers on theworkpiece. A ratchet and pawl mechanism is provided between theadjusting collar and the collet member to prevent their relativerotation and loosening of the collet fingers from the workpiece duringoperation of the lathe.

76,361 11/1954 Netherlands ..82/38 Primary ExaminerLeonidas VlachosAtt0meyW. Britton Moore 84 M 52 96 Ff e2 90 I06 I03 4 88 Q no 6 A 1 8 I,A 6 1 ,7 Q \///#01// A PATENTED MAY 23 I972 3 4 15 SHEET 1 OF 3 INVENTORJOSEPH KLADICH ATTORNEY PATENTEDMAY 23 m2 SHEET 2 BF 3 \NVENTOR JOSEPHKLADICH dflm ATTORNEY PATEHTED MAY 2 3 I972 SHEET 3 BF 3 H Y mm N ms m WW W A E m; WU

The present invention relates to a steady rest for use with amachinist's lathe.

It is established practice to utilize a steady rest when carrying outmachining operations on long or on relatively flexible workpieces orwhen machining the exposed end surface of a workpiece supported in thechuck of a lathe. Many of the previously known steady rests havepresented the serious disadvantage that they are relatively difficult toset up, requiring considerable care and time to ensure that theworkpiece is axially centered in both the lathe chuck and in the steadyrest itself. Such centering of a workpiece in a steady rest hasfrequently required the separate adjustment of three centering screws.

Another problem which frequently arises with existing steady rests isthat shims must often be used to prevent damage by the jaws of thesteady rest to the outer surface of the workpiece. Such use of shims mayin itself make the centering operation even more difficult andtime-consuming.

It is, accordingly, a principal object of the present invention toprovide a steady rest for use with a lathe and which is free of theaforementioned disadvantages.

It is particularly an object of the present invention to provide asteady rest in which the centering of a workpiece is effectedautomatically.

It is yet another object of the present invention to provide a steadyrest which does not normally require the use of shims for avoidingdamage to a workpiece supported therein.

Yet another object of the present invention is to provide a steady restwhich can easily be adapted for use with cylindrical workpieces having awide range of external diameters.

These and other objects are achieved in accordance with the presentinvention by a steady rest comprising a rotatable self-centering chuckmechanism for securing a workpiece extending therethrough and mountedfor free rotation with a non-rotatable housing adapted to be secured toa lathe.

The self-centering chuck mechanism of a steady rest according to theinvention may usefully comprise a generally cylindrical sleeve and anaxially adjustable collet member disposed therein, said collet memberhaving at least three, and preferably four, equi-angularly radiallyspaced and axially extending fingers for gripping a workpiece, theradial positions of all said fingers being simultaneously adjustable byrelative axial movement of said sleeve and said collet member.

The aforementioned sleeve may usefully be mounted for rotation withinsaid housing in any conventional manner but the use of roller bearingsfor this purpose has proved to be highly effective. Such rollersbearings are preferably arranged so as to provide axially oppositelydirected thrust forces.

The adjustment of the radial positions of the aforementioned fingers onrelative axial movement of the sleeve and the collet member ispreferably obtained by the provision on said collet member and on saidsleeve of co-operating internal and external frusto conical surfaces.The relative axial movement of the sleeve and the collet member can inturn usefully be obtained by the provision of co-operating screw threadson the collet member and in an adjusting collar abutting one end of thesleeve so that, on rotation of such adjusting collar relative to thecollet member, the collet member is moved axially relative to thesurrounding sleeve in turn to cause the desired radial movement of thecollet fingers. In order to facilitate adjustment of the steady rest,means are preferably provided for temporarily securing the sleeve to thehousing to prevent rotation of the sleeve during rotation of theadjusting collar for the purpose of effecting said radial movements ofthe collet fingers. Such means may, for instance, comprise a pin mountedfor axial movement through said housing from a retracted positionpermitting rotation of said sleeve and an extended position in which thepin is received within a peripheral depression in said sleeve to preventrotation of the latter.

Locking means are also usefully provided to prevent undesired relativerotation of the adjusting collar and the collet member during operationon a workpiece secured within the steady rest to avoid all risk ofaccidental loosening of the collet fingers from the workpiece. A ratchetand a co-operating pawl may be provided for this purpose.

By the use of collet members of equal external diameters but havingcollet fingers of different radial thicknesses, the steady rests of thepresent invention may be utilized for supporting cylindrical workpieceshaving a wide range of external diameters.

The invention will now be described merely by way of illustration withreference to the accompanying drawings in which:

FIG. 1 is a partial perspective view of an engine lathe fitted with asteady rest according to the invention,

FIG. 2 is a transverse sectional view showing the manner in which thesteady rest of FIG. 1 is secured to the lathe,

FIG. 3 is an enlarged perspective view of the steady rest of FIG. 1 withcertain parts cut away to show the internal construction,

FIG. 4 is a partial elevation of the steady rest of FIG. 3 when viewedin the direction of the arrow 4 of that figure,

FIG. 5 is a partial elevation of the steady rest of FIG. 3 when viewedin the direction of the arrow 5 of that figure,

FIG. 6 is a partial vertical section along the line 6-6 of FIG. 3 withcertain parts omitted for the sake of clarity and showing the colletmember out of engagement with a workpiece, and

FIG. 7 is a view similar to that of FIG. 6 but showing the collet memberin engagement with the workpiece.

Referring first to FIG. 1, it will be seen that the steady restmechanism according to the invention and generally indicated at 10 ismounted on a lathe having a headstock 12, a workpiece-holding chuck l3and longitudinal ways 14 and 16. As hereinbefore indicated, the steadyrest mechanism 10 comprises a rotatable self-centering chuck mechanism18 and a non-rotatable housing generally indicated at 20.

The housing 20 may be mounted on the lathe in any convenient manner and,in the arrangement shown in the drawings, this mounting is effected by asupport frame 22 secured to the base of the lathe by a bolt 24 and a nut26. The housing 20 is secured to the frame 22 by means of a semicircularsaddle 28 and a semicircular clamp 30 pivoted at 32 to the saddle 28.The latter is provided with a generally U-shaped member 34 pivoted at 36for rotation in a vertical plane between an unlocked position permittingretraction of clamp 30 and a locked position in which clamp 30 is heldin its downward position by the engagement of a clamping screw 38 with atongue 40 extending from the clamp 30. W.

The dimensions of the frame 22 are such that the center of the steadyrest 10 is axially aligned with the center of the chuck 13 holding theworkpiece W."

It will be appreciated that a steady rest in accordance with theinvention may be mounted on a lathe in any appropriate manner and thatthe arrangement shown in FIGS. 1 and 2 is given merely by way ofillustration.

Referring now to FIG. 3, it will be seen that the steady rest comprisesa self-centering chuck mechanism 18 and the nonrotatable housing 20. Thechuck mechanism 18 for holding the workpiece W (not shown in FIG. 3) isin the form of a generally cylindrical collet member 42 having fouraxially extending fingers 44, each of which in transverse sectionextendes substantially around one quadrant of the workpiece W, allowanceof course being made for the small peripheral separation 46 providedbetween the fingers 44.

The collet member 42 is surrounded by a sleeve 48, the axial position ofwhich relative to said collet member 42 can be adjusted in a manner tobe described hereinafter.

In the construction shown in the drawings, the chuck mechanism 18 ismounted for rotation within the housing 20 by means of axially separatedroller bearings 50 and 52, each comprising a plurality of rollers 54supported by rotatable bearing blocks 56 and 58 and non-rotatablebearing blocks 60 and 62. It should be noted that, in accordance with apreferred feature of the invention, the bearings 50 and 52 are soarranged that, in use, the resulting thrust forces are directed inaxially opposite directions.

The thrust forces acting on the sleeve 48 are received against aradially extending forward flange 64 while, at the rearward end of thesleeve 48, the forces are received by a lock nut arrangement 66threadably received at 68 on the sleeve 48. The non-rotatable bearingsblocks 60 and 62 are supported by radial flanges 70 and 72 respectivelyforming part of the housing 20.

In order to provide the desired radial movement of the fingers 44 forgripping a workpiece, the collet member 42 is provided with an externalfrusto conical surface 74. This surface 74 is disposed so as to abut acorresponding internal frusto conical surface 76 provided at the forwardend of the sleeve 48 so that, on relative axial movement of the sleeve48 and the collet member 42, the required radial movement of the colletfingers 44 is obtained. In order to facilitate such radial movement ofthe collet fingers 44, these fingers are constructed with reduced radialthicknesses at their rearward extremities as shown at 78.

The required relative axial movement of the sleeve 48 and the colletmember 42 is usefully obtained by the provision of an external thread 80on the rearward end of the collet member 42. This thread 80 engages aninternal thread 82 provided in a knurled adjusting collar 84 which has aradial surface 86 which in turn abuts the rearward end surface 88 of thesleeve 48. For reasons which will become apparent as the descriptionproceeds, the knurled collar 84 is provided with a ratchet pawl 90normally maintained by a tension spring 92 (FIG. 4) in engagement with amale ratchet gear 94 with axially extending teeth provided at therearward end of the collet member 42. The pawl 90 is rotatably mountedon collar 84 by a bolt 96.

At the forward end of the housing 20, a locking pin 98 is mounted forradial movement in a passageway 100. A peripheral depression 102 isprovided in the forward end of the sleeve 48 for receiving the end ofthe pin 98 when the latter is in its extended position. A helicalcompression spring 104 is disposed about the pin 98 normally to urge thelatter radially inwardly. In order to prevent such inward radialmovement of the pin 98, the latter is provided with a handle 106, theshaft of which engages a cam surface 108. In the position shown in FIG.3, the pin 98 is maintained in its radially outward position byengagement of the shaft of the handle 106 with the cam surface 108. Onrotation of the handle 106, the pin is urged under the action of spring104 into the depression 102 in the sleeve 48 so as to occupy theposition shown in FIG. 5. In the construction shown in the drawings, thesupport block 110 carrying the pin 98 is mounted on the forward end ofthe housing 20 by bolts 1 12.

It will be appreciated that provision will normally be made for thelubrication of the bearings 50 and 52 and of all relatively movingsurfaces. To this end, a grease nipple l 14 is illustrated in FIG. 3.

The operation of a steady rest according to the invention will now bedescribed with particular reference to FIGS. 3, 6 and 7. Having insertedthe workpiece W into the steady rest and having secured the rearward endin the chuck 13, the pin 98 is released by rotation of the handle 106 topermit the former to move under the influence of spring 104 into thedepression 102. The knurled collar 84 is then rotated so as to retractthe collet member 42 in a rearward direction from the position shown inFIG. 6 to that shown in FIG. 7. During this rearward movement of thecollet member 42, the surface 74 of the latter engages the surface 76 ofthe sleeve 48 and this urges the fingers 44 radially inwardly to gripthe workpiece as shown in FIG. 7. During this relative rotation of thecollet member 42 and the sleeve 48, the pawl 90 will slip over the teethof the ratchet gear 94. The pin 98 is next retracted from the depression102 by rotation of the handle 106 to permit free rotation of the colletmember 42 and the sleeve 48 on roller bearings 50 and 52 duringmachining operations on the workpiece W. When such operations have beencompleted, the workpiece may be released from the steady rest byrotating handle 106 to allow pin 98 to enter depression 102, releasingratchet gear 94 by retracting pawl and then rotating the knurled collar84 in the opposite direction to that previously described.

It will be appreciated that, by the use of collet members having fingersof difi'erent radial thicknesses, the steady rest shown in the drawingsmay be utilized for accommodating workpieces with a wide range ofexternal diameters.

While I have described herein and shown for purposes of iilustrating theprinciple of my said invention, certain means and arrangements thereoffor carrying my invention into practice, it is obvious that variousmodification and changes may be made therein by persons skilled in theart. I, therefore, do not wish to be limited to the precise details setout herein but desire to avail myself of such modifications andembodiments as come within the scope of the claims appended hereto.

What I claim is:

1. A steady rest for use with a lathe and comprising a rotatableself-centering chuck mechanism for securing a workpiece extendingtherethrough and mounted for free rotation within a non-rotatablehousing adapted to be secured to such a lathe, and which self-centeringchuck mechanism in turn comprises a generally cylindrical sleeve and anaxially movable collet member disposed therein, said collet memberhaving at least three equi-angularly radially spaced and axiallyextending fingers for gripping a workpiece extending through said chuckmechanism, the radial positions of all said fingers being simultaneouslyadjustable on relative axial movement of said sleeve and said colletmember by virtue of the provision on said collet member and on saidsleeve of co-operating frusto-conical surfaces, an adjusting collarscrewed on said collet member and terminally abutting said sleeve tocause relative axial movement of said sleeve and said collet member onrelative rotation of said adjusting collar and said collet member, andmeans for preventing undesired relative rotation of said collet memberand said adjusting collar during operation on a workpiece secured withinsaid chuck mechanism.

2. A steady rest as claimed in claim 1 in which means are additionallyprovided for temporarily securing said sleeve to said housing to preventrotation of said sleeve during rotation of said adjusting collar for thepurpose of effecting said radial movement of said fingers of said colletmember.

3. A steady rest as claimed in claim 2 in which said means fortemporarily securing said sleeve to said housing comprises a pin mountedfor axial movement through said housing from a retracted positionpermitting rotation of said sleeve and an extended position in whichsaid pin is received within a peripheral depression in said sleeve toprevent rotation of the latter.

4. A steady rest as claimed in claim 1 in which said means forpreventing undesired relative rotation of said collet member and saidadjusting collar comprises a ratchet gear and a co-operating pawlsecured to said collet member and said adjusting collar.

5. A steady rest as claimed in claim 4 in which said ratchet gearcomprises axially extending teeth formed on said collet member and inwhich said pawl member is pivotally mounted on said adjusting collar forreleasable engagement with said ratchet teeth, and in which steady restspring means are connected to said pawl member to urge said pawl memberinto releasable engagement with said ratchet teeth.

1. A steady rest for use with a lathe and comprising a rotatable self-centering chuck mechanism for securing a workpiece extending therethrough and mounted for free rotation within a non-rotatable housing adapted to be secured to such a lathe, and which selfcentering chuck mechanism in turn comprises a generally cylindrical sleeve and an axially movable collet member disposed therein, said collet member having at least three equi-angularly radially spaced and axially extending fingers for gripping a workpiece extending through said chuck mechanism, the radial positions of all said fingers being simultaneously adjustable on relative axial movement of said Sleeve and said collet member by virtue of the provision on said collet member and on said sleeve of co-operating frusto-conical surfaces, an adjusting collar screwed on said collet member and terminally abutting said sleeve to cause relative axial movement of said sleeve and said collet member on relative rotation of said adjusting collar and said collet member, and means for preventing undesired relative rotation of said collet member and said adjusting collar during operation on a workpiece secured within said chuck mechanism.
 2. A steady rest as claimed in claim 1 in which means are additionally provided for temporarily securing said sleeve to said housing to prevent rotation of said sleeve during rotation of said adjusting collar for the purpose of effecting said radial movement of said fingers of said collet member.
 3. A steady rest as claimed in claim 2 in which said means for temporarily securing said sleeve to said housing comprises a pin mounted for axial movement through said housing from a retracted position permitting rotation of said sleeve and an extended position in which said pin is received within a peripheral depression in said sleeve to prevent rotation of the latter.
 4. A steady rest as claimed in claim 1 in which said means for preventing undesired relative rotation of said collet member and said adjusting collar comprises a ratchet gear and a co-operating pawl secured to said collet member and said adjusting collar.
 5. A steady rest as claimed in claim 4 in which said ratchet gear comprises axially extending teeth formed on said collet member and in which said pawl member is pivotally mounted on said adjusting collar for releasable engagement with said ratchet teeth, and in which steady rest spring means are connected to said pawl member to urge said pawl member into releasable engagement with said ratchet teeth. 